Differences between these hydronic devices

[amadogon49]

Hello:

Can someone explain to me the differences between a differential bypass valve, which is supposed to unite the ends of the main supply and return pipes, in a multi zoned hydronic system using baseboard as the emitters throughout the house, and the use
of balancing valves, which are installed at the return side of each of the zones.

From what I'm understanding they serve the same purpose, to make sure the proper pressure is being applied to each of the zones, depending on whether one or more zones are opened/closed.

Are both types of devices intended to coexist together on the same system, or do you use one or the other.

Thanks,
Amado

 

[johnjh2o]

The balancing valves are used to balance the system. The bypass between the feed and return line is used to temper the water returning to the boiler.

John